FRIDAY, July 20 (HealthDay News) -- As word spread Friday that a heavily armed man had shot up a suburban Denver movie theater crowded with families and children for a midnight showing of the new Batman movie, mental health experts offered guidance on how to cope with the tragedy.

While this latest act of carnage unnerved a nation still scarred by the terrorist attacks of Sept. 11, 2001, psychologists said children and teens may be especially vulnerable to the early Friday shootings in Aurora, Colo., that left 12 people dead and as many as 59 others wounded.

"It would be perfectly normal for people to be more on edge right now," said Simon Rego, director of psychology training at Montefiore Medical Center and Albert Einstein College of Medicine in New York City. "It's a natural reaction when you hear about, experience or witness a traumatic event. You're primed to be more vigilant about what's happening to you."

But parents can do much to reassure their children that such an incident isn't likely to repeat itself anytime soon, experts said. And it's important to offer that reassurance now.

"This is clearly a very disturbed individual [the 24-year-old shooting suspect] and parents have to reassure kids that this is a very random event and they shouldn't bring their lives to a halt because of this," said Alan Hilfer, director of psychology at Maimonides Medical Center in New York City. "Parents have to reassure kids that they're going to do everything they can to make sure they're safe."

A good place to start is by communicating, Rego said.

"Make sure you're having a talk," he advised. "Make sure a support system is there so if people are looking anxious or stressed out, encourage them to talk about what they're experiencing or feeling."

Echoing Hilfer, Rego said, "The second thing to do is recognize that there are these events that, unfortunately, happen in our lives that are traumatic and unpredictable and we also have to be able to go on with our lives."

A bigger question is how this latest incident will affect the psyche of a generation of young Americans already exposed to extremely high levels of violence.

The list includes two shocking school shootings. The first: April 16, 2007, when a gunman killed 23 people and then himself on the Virginia Tech campus in Blacksburg, Va. The second: April 20, 1999, when two students opened fire at Columbine High School in Littleton, Colo., not far from the site of Friday's tragedy, killing 12 classmates and a teacher and wounding 26 others before killing themselves.

And, of course, the horror of 9/11, when terrorists hijacked jets and crashed them into the Twin Towers of Manhattan's World Trade Center, killing nearly 3,000 people.

A New York Times review of The Dark Knight Rises noted that the film includes "the explosions, the dust, the panic and the sweeping aerial shots of a very real-looking New York City -- [that] invokes the September 11 attacks."

The new Batman movie opened around the world Friday with midnight showings in the United States.

The Colorado shootings prompted officials to cancel the Paris premiere, with workers removing the red carpet display at a theater on the Champs-Elysees Avenue, the Associated Press reported.

NBC New York reported that the New York City Police Department was increasing security at city theaters showing the movie. "As a precaution against copycats and to raise the comfort levels among movie patrons in the wake of the horrendous shooting in Colorado, the New York City Police Department is providing coverage at theaters where the 'The Dark Knight Rises' is playing in the five boroughs," Police Commissioner Ray Kelly said in a statement.

It's unclear if the violent acts of the past 13 years are having a cumulative impact on young Americans.

Whatever the impact, the effect or effects are likely to be very individual, Rego said.

"People [can] develop an anxiety or apprehension about the things that go wrong for us. At the same time, people have tremendous resiliencies, too," he said. "We have different psychological and biological vulnerabilities in our reactions to these events."

The suspect in Friday's shootings was described as James Holmes, a 24-year-old former medical student. He had attended the University of Colorado School of Medicine in Denver until last month, a school spokeswoman said, adding that she didn't know why he withdrew from the school, the AP reported.

Wearing a gas mask, Holmes allegedly walked into a midnight showing of the Batman movie, unleashed a gas canister and then opened fire, making it one of the deadliest mass shootings in recent U.S. history, the news service said.

As the gas started to spread, some patrons thought it was a stunt that was part of the movie. Then they saw a silhouette of a person in the smoke near the screen, first pointing a gun at the crowd and then shooting, the AP reported.

Authorities did not release a motive, and the FBI said there was no indication that the shooting was tied to a terrorist group.

Holmes reportedly had an assault rifle, a shotgun and two pistols, a federal law enforcement official said, speaking on the condition of anonymity, the AP reported.